1. Field of the Invention
The invention relates to motor-driven mechanisms for repetitively advancing the film and actuating exposure buttons of concealed cameras to produce timed sequences of photos.
2. Description of the Prior Art
Various industrial security systems and the like have been utilized to detect unauthorized entry into a restricted area to monitor or record unauthorized or criminal activities by persons making such unauthorized entry. Such systems have included expensive television cameras and a variety of expensive cameras with sophisticated and expensive mechanisms for making a timed sequence of photos in response to a control signal triggered by a mechanism detecting the unauthorized entry or any a remote transmitter signal initiated by someone observing the unauthorized entry or activity. The state of the art is generally indicated by U.S. Pat. Nos. 3,117,314; 3,391,623; 4,054,752; 3,858,223; 3,821,760; 3,739,698; 3,594,747 and 3,391,624. However, none of these patents disclose particular details of any motor-driven external mechanisms for sequentially activating an exposure button and film winding lever of a camera. Various apparatus including concealed cameras with mecahnisms for advancing the film and activating the exposure buttons have been utilized in conjunction with security systems. One system utilizes a low cost camera known as the "Great Wall" camera, made in China. The "Great Wall" camera can be wound up by hand so that the film automatically advances every time the exposure button is activated. However, the camera makes a great deal of noise as it advances the film automatically. This noise is sufficiently great that it is not adequately muffled even by insulation provided in a concealing enclosure, and thus can alert the persons being photographed. It is, of course, desirable that criminals or unauthorized persons being photographed not to be alerted to the fact that they are being photographed. This may be crucial to the safety of a person, such as a liquor store employee who initiates the operation of the surveillance camera during an armed robbery.
Various cameras which are much more expensive than the "Great Wall" camera have the capability of being connected to battery powered units which can be connected to such cameras to automatically advance the film and operate the exposure control to produce a timed sequence of photos. However, these units also produce an unacceptably high level of noise during operation. The other shortcoming of such cameras and battery powered advancing units is that the batteries must be periodically replaced. The "Great Wall" camera has the shortcoming that it must be wound by hand and it is possible that those responsible for operability of the system may forget to wind the unit, resulting in inoperability at a crucial time. Thus, there is a need for a reliable, low cost, low noise surveillance camera system capable of taking a timed sequence of photographs in response to a control signal.